ABSTRACT
BACKGROUND: The prolonged tendon-healing process, the high costs associated with treatment, the increase in the number of injuries over the past decades, and the lack of consensus on the optimal treatment of tendon injuries are a global problem. Restoring the normal tendon anatomy and decreasing the healing time are key factors for treatment advancement. HYPOTHESIS: Application of a purified protein from natural latex (PPNL) accelerates the healing process, increasing collagen synthesis and decreasing metalloproteinases. PPNL associated with a simpler suture technique should decrease the healing time. STUDY DESIGN: Controlled laboratory study. METHODS: Injury, surgery, and treatment with PPNL were conducted with male Sprague-Dawley rats. Two suture techniques were used: U-suture, a simpler and lesser traumatic technique, and Kessler-Tajima, to avoid strangulation of the microcirculation. Achilles tendons were completely sectioned, and 100 µL of 0.1% PPNL was applied on the tendon during surgery. Tendon morphology, distribution, and quantity of collagen types I and III, as well as expression of TIMP-1, TIMP-2, MMP-2, and MMP-9 and ultrastructural aspects of cells and collagen fibrils, were assessed after 2 and 4 weeks. RESULTS: PPNL treatment improved collagen type I synthesis and reduced MMP-2 expression. All groups showed a 6.8-times increase in tendon weight as compared with the control group after 2 weeks and a 5.2-times increase after 4 weeks. All groups showed an increase in diameter after 4 weeks, except for the ones treated with PPNL, which showed a slight reduction in diameter. The peak of concentration of collagen fibrils with a 80-nm diameter was 27.79% in the control group; all other experimental groups presented fibrils between 50 and 60 nm. However, the best results were observed with Kessler-Tajima suture associated with PPNL. CONCLUSION/CLINICAL RELEVANCE: There are no known medicines or substances capable of aiding the tendon healing process besides surgery. The discovery of a substance able to improve this process and decrease its duration represents an important advancement in orthopaedic medicine.
Subject(s)
Achilles Tendon/injuries , Achilles Tendon/surgery , Rubber/administration & dosage , Sutures , Wound Healing/physiology , Animals , Collagen Type I/metabolism , Collagen Type III/metabolism , Hevea , Male , Matrix Metalloproteinase 2/metabolism , Matrix Metalloproteinase 9/metabolism , Models, Animal , Rats , Rats, Sprague-Dawley , Suture Techniques , Tissue Inhibitor of Metalloproteinase-1/metabolism , Tissue Inhibitor of Metalloproteinase-2/metabolismABSTRACT
The aim of this study was to analyze the rat temporomandibular joint (TMJ) synovial membrane at different ages using light, scanning, and transmission electron microscopy. Under light microscopic analysis, the TMJ structures were observed such as condyle, capsule, disk, the synovial membrane collagen type, and cells distribution. In the scanning electron microscopy, the synovial membrane surface exhibited a smooth aspect in young animals and there was an increase with ageing in the number of folds. The transmission electron microscopic analysis showed more synoviocytes in the synovial layer in the young group and still a great number of vesicles and cisterns dilation of rough endoplasmic reticulum in the aged group. In the three groups, a dense layer of collagen fibers in the synovial layer and cytoplasmic extensions were clearly seen. It was possible to conclude that synovial membrane structures in aged group showed alterations contributing to the decrease in joint lubrication and in the sliding between disk and joint surfaces. These characteristic will reflect in biomechanics of chewing, and may cause the TMJ disorders, currently observed in clinical processes.
